Tolerances in your RC equipment may cause glitches and can decrease the range of your transmitter. A Torodial core choke is used on the servo lead to reduce noise from the radio system they are available at most electronic supply or you might try your local hobby shop.
You simply rap the servo lead around the choke 3 or 4 times thus stopping the noise and glitches to the servo.

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I have a 1/8 scale Mad Torque rock crawler and love it, it goes over anything and climbs very steep inclines. It works great but occasionally the steering will start twitching back and forth. At first I thought it was interference but it will happen at different locations. I also added the front linkage kit and servo so it has 4 wheel steering, what a difference!
Does anyone elso have this problem? Any solutions?

Now the the throttle is also twitching uncontrollably, going foward and backwards. But it stops when I turn off the transmitter. I am thinking my transmitter is no good?

first things first. are the transmitter batteries good? if they are old, put new ones in.

second is the trucks battery charged? when it gets low they will twitch some times.

third look the entire truck over for loose connections. if the truck has tamiya battery and esc plugs on it, they are well known to give bad connections. this look over is also to make sure all connectors are plugged into the receiver good, that wires are not knicked or damaged, that the battery and esc connectors are all good.

after this if you still have problems with the truck twitching forward/backward, then recenter all your trims on the transmitter, center dual rate steering (if you have it), and rebind the transmitter to the truck.

if the problem still exists, then unplug your rear steer servo, still doing it, then unplug the front steering servo. what you are doing is eliminating the servos from causing the problem. if a servo is going bad sometimes they will bind and draw quite a bit of power. this excess draw can cause the esc's internal bec to shut off. when this happens the receiver will shut off also, when the receiver comes back on it can cause glitches.

first things first. are the transmitter batteries good? if they are old, put new ones in.

second is the trucks battery charged? when it gets low they will twitch some times.

third look the entire truck over for loose connections. if the truck has tamiya battery and esc plugs on it, they are well known to give bad connections. this look over is also to make sure all connectors are plugged into the receiver good, that wires are not knicked or damaged, that the battery and esc connectors are all good.

after this if you still have problems with the truck twitching forward/backward, then recenter all your trims on the transmitter, center dual rate steering (if you have it), and rebind the transmitter to the truck.

if the problem still exists, then unplug your rear steer servo, still doing it, then unplug the front steering servo. what you are doing is eliminating the servos from causing the problem. if a servo is going bad sometimes they will bind and draw quite a bit of power. this excess draw can cause the esc's internal bec to shut off. when this happens the receiver will shut off also, when the receiver comes back on it can cause glitches.

Yes I already tried all the things you mentioned except unplugging and checking the servos. I will try that next, thanks.

I have tried almost everything people have sugested here with no luck. The rock crawler is fairly new, driven maybe a dozen times, not beat on and never exposed to mud and water. I find it strange how the problem went from just steering twitches to throttle twitches also without it even been driven. I am thinking it is either a transmitter/receiver problem or a problem with the speed control but am not sure how to determine which it is. The radio system and speed control are original equipment.

well if you are having twitching forward/backward problems, and you have checked all your batteries, and unplugged everything from the receiver except the esc and your still having these issues, the only other thing you can do is try a different transmitter or a different esc.

from my experience your problem will usually lie in the esc. but it would be very easy to use a different transmitter just to be sure. if you (or a friend) doesn't have one laying around, you might hit your local hobby shop. they usually have a few laying around they would probably let you try out, or they would know of somebody that does.

hoghead,
sounds good, I will have to check my recources, Thanks for your help and advice.This R/C groups is awesome, a lot of people friendly and willing to take their time and help others in the hobby.I have been out of the hobby for about 10 years and the advances in electronics have changed things considerably.

I tried looking for a replacement speed control under spare parts for the madtorque at the place I bought the truck at nitrorcx.com but they did not have a stock replacement. Any sugestions on an inexpensive replacement? My truck has the battery and motors that came with the truck.